Two-section catalyst bed



United States Patent 3,184,403 TWO-SEQTION CATALYST BED Lloyd E. Gardner and Robert J. Hogan, Bartlesville,

Okla, assignors to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Sept. 12, 1360, Ser. No. 55,128 1 Claim. (Cl. 208-89) This invention relates to a two-stage treatment of heavy hydrocarbon liquid such as a heavy residual hydrocarbon oil. In one of its aspects, the invention relates to a process of hydrotreating a heavy residual hydrocarbon stock in the presence of a sulfur-resistant hydrodesulfurization catalyst and subsequently treating the thustreated stock under hydrocracking conditions over a catalyst consisting essentially of cobalt molybdate on fluorinated alumina. In another of its aspects, the invention relates to the treatment under hydrocracking conditions of at least a portion of a heavy residual hydro carbon stock in the presence of a cobalt molybdate on fluorinated alumina when said stock has been treated under hydrotreating conditions in the presence of a sulfur-resistant hydrosulfurization catalyst. In another aspect of the invention, Wafra topped crude having an initial boiling point of 400 F. is hydrocracked following a hydrotreatment thereof in presence of a hydro- .treatment catalyst. In a further aspect, the invention first hydrotreats a Wafra topped crude and then effectively hydrocracks the same in the presence of a hydrocracking catalyst, as herein described. in a further aspect of the invention it relates to a composited catalyst bed containing a layer of a cobalt molybdate on alumina catalyst and a layer of HF-treated cobalt molybdate on alumina catalyst.

We have now discovered that a cobalt molybdatefluorine-alumina catalyst is particularly suited to hydrocracking a residual stock which has been first hydrotreated in a preliminary stage.

3,134,403 Patented May 18, 1965 ICE According to the present invention, a heavy residual hydrocarbon stock, such as Wafra topped crude, for example, boiling at about 400 F. and higher, is first hydro treated over a sulfur-resistant hydrodesulfurization catalyst, e.g., cobalt molybdate on alumina and is subsequently hydrocracked over a catalyst of cobalt molybdate on fiuorinated alumina. It is a concept basic to the present invention that the cobalt molybdate on fluorinated alumina appears to be particularly well suited to the hydrocracking step after the preliminary treatment in presence or" a sulfur-resistant hydrodesulfurization catalyst. Also, according to the invention there is provided a novel catalyst combination comprising a layer of a cobalt molybdate on alumina catalyst and a layer of an HF-treated cobalt molybdate on alumina catalyst.

Although a large variety of residual hydrocarbon stocks are suited to conversion by the present process, presently preferred to be treated are crude oil residues such as topped crude, atmospheric and vacuum-reduced crudes, and the like. However, the process is applied with very good results to those residual stocks which have substantial carbon residue values from crudes, such as asphalt-base and mixed-base crudes. Particularly, the process now finds excellent suitability to the beneficiation or conversion of Wafra topped crudes.

In the following example, the data show results obtained.

EXAMPLE The tests below compare the present invention (dual bed tests) with tests of each of the same catalysts alone, The tests were continuous flow in a down-flow, fixed bed reactor. The dual-bed runs were made with a catalyst of cobalt molybdate on alumina in the upper half of the bed, and cobalt molybdate on HF-treated alumina in the lower half of the catalyst bed.

The carbon residue referred to in the data are Rams bottom values.

Table I .Hydr0cracking Wafra topped crude [1000 p.s.i.g., 125 cc. catalyst, 6 hr. runs] OoMo Dual CoMo IIF-CoMo Dual CoMo HF-CoMo Dual bed bed bed bed bed bed bed bed Run Number 1 2 3 4 5 6 7 8 Average temperature, F 726 725 726 725 726 750 748 751 LIISV 0. 22 0. 26 0. 51 0. 0. 48 0. 49 0. 51 0. 49 Percent oonv. of 850 F 83 36 53 59 42 62 70 Percent desuliurlzation 95- 98 92 86 97 96 85 08 Percent carbon res. removal 94 99 77 75 88 93 7 9 94 Product inspection, 0

API 60 31. 5 38.0 28. 1 29. 7 31.5 30.1 31. 4 35. 4 Wt. percent sulfur. 0.18 0.06 0.31 0. 52 0.13 0.14 0. 54 0. 09 Wt. percent C res 0.67 0.13 1.9 2. l 0. 96 0.60 1. 7 0. 48 Yields, wt. percent of charg C10 s 0.2 10.8 2.3 7.4 7.8 3.9 9. 5 7. 5 CEsAOO" F 12. 2 24. 8 5. 4 10. 8 9. 8 9.0 16.1 18. 5 400- 61. 2 48. 8 53.0 50.8 55. 3 52.0 48.1 52. 9 850 F,+ 21. 4 9. 4 35. 4 26. 8 22. 8 31. 7 21.9 16. 5 Coke 1.6 2.6 0.7 1.1 0.8 0.8 1.3 1.0 Sulfur as His 3. 4 3. 6 3. 3 3.1 3. 5 3. 5 3.1 3. 6

It is an object of this invention to provide a two-stage treatment of a heavy hydrocarbon liquid. It is another object of this invention to provide a pre-treatment which renders hydrocracking of a residual stock in the presence of a cobalt molybdate-fiuorine-alumina catalyst more effective. It is a further object of this invention, specifically, to provide a process in which Wafra topped crude can be efifectively hydrocracked. A still further object of the invention is to provide a novel combination of catalysts especially suited to the two-stage treatment of a heavy hydrocarbon liquid.

Other aspects, objects and several advantages of this invention are apparent from this description and the appended claims.

Wafra 400 F.+ crude properties:

API 60/6018.6 Wt. percent sulfur-3.6 Wt. percent C res-8.1 Wt. percent 850 F.,+57.0

Catalyst properties:

CoMoO -Al O -2.5% Co, 6.1% M0, 180 mF/g. HF-CoMoO -Al O --2.6% Co, 4.9% M0, 5.5% F,

180 mF/g.

The fluorinated catalyst was prepared by soaking 184 parts by weight of the above catalyst in 127.4 parts of 12.3 weight percent. aqueous hydrofluoric acid followed by drying.

. These catalysts had been used several times 'p rior toj making the above tests. 5,

Referring to Table Lin Run 2,.the dual bed of-the;

invention doubles the gasoline boiling rangefrom 12.2-

a with amounts outside these ranges.

It will be noted from the example that the reactor contains a layer of cobalt molybdate'on alumina of Run 1, to 24.8 lover the use of the cobalt molybdate bed. The dual bed in the next three runs Runs (3, 4 and 5) yields 55;3 of the useful 400850 F. material which is higher than the single bed of either of the othertwo': catalysts of Runs 3 and 4 of thetable,'while materially in the upper half of the bed and cobalt molybdate on HF treated alumina .in' the lower half ofthe bed and that the twolayersare thus'contiguous.

reducing the 850 F.+,n1aterial which is not as de+ q sirabler- Similarly, for the last three runs 6, 7 and 8) of the table in which there is a notable increase in the gaso-- line boiling range material. 5 I

As can be seen from an examination of'the test results,

'the cobalt molybdate-fluorine-alumina catalyst is 'paris superior to the same total quantity of either catalyst alone.

In tests at several conditions, the combinationv of twocatalysts gave better desulfurization, carbon residue reduction and conversion alyst alone.

. 'Generally, the sulfur resistant hydrotreating catalysts useful in the first stage of this invention are-the 'Sup- 2 high flow rates.

of 850 F. than either catj 'cially a Wafra topped crude.

ported oxides and sulfides. of GroupsVI and VIII metals particularly chromium, molybdenum, tungsten,-cob.a1t

and nickel. Suitable supports or carriers are the activated clays such as montmorillonite and bauxite, and synthetic gels such as activated alumina, silica-alumina, zirconia, titania, etc. Particularly good catalysts are cobalt molybdate on alumina and nickel-tungsten sulfide' on alumina.

These catalysts and methods of known in the prior art.. I The fiuorinated cobalt molybdate catalyst can be made in several ways, but, one simple and quite satisfactory preparing them are well method is simply soaking an alumina-supported cobalt Conventional" pressures, temperaturesgflow 5 rates and hydrogen rates canlbe used. Temperatures will ordinar'ily range from 650 F. to 850 F.,' although temperatures above 800 F. are used. in'the second stage only at Pressures can range, from 500 05,000 psi. Liquid hydrocarbon flowfratesof 0.2 to 10 volumes an hour are satisfactory, but rates of 0.5 to 4 volumes an hourare preferred, Hydrogen flows of 500 to 5000 cubic feet per barrel are ordinarily employed.

Reasonable variation 'anclmodificationarepossible within the scope of the foregoingdisclosure and the appended claims to the inventiomthe .essence of which is that an -I-IF-cobalt molybdate on alumina catalyst has been found to effectively combine with a sulfur-resistant hydrodesulfurization catalyst which is used in a first stage to hydrotreat a heavy residual hydrocarbon stock, espe- We claim: V v

A catalytic *bed especially suited 'for the hydrotreatment and hydrbcracking of. a-heavy residual hydrocarbon stock which comprises a layer of cobalt molybclate on alumina catalyst and a layerycontiguous. therewith of HF-treated cobalt molybdat'e on alumina catalyst.

' References Cited by the Examiner i a UNITED STATES PATENTS. 2,839,450

6/58 Oettinger 208 2,911,352 11/59 Goretta et al. 20868 2,925,374 2/60 Gwin et al. 4 20889 2,945,803 7/60 Beuther 'et al. 20889 2,987,468 6/61 Chervenak "5208 -216 3,003,953 10/61 Evans 208210 3,008,895 11 /61 Hanst'ord et al. 20889 3,023,158 2/62 Watkins 20889 ALPHONSO D. SULLIVAN, Primary Examiner. j

iixed bed 

